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  Image correcting methodRelated Patent Categories: Image Analysis, Applications, Manufacturing Or Product Inspection, Inspection Of Semiconductor Device Or Printed Circuit BoardImage correcting method description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060215899, Image correcting method. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-085215 filed on Mar. 24, 2005 in Japan, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an image correcting method. The image correcting method can be used in, for example, a pattern inspection apparatus for inspecting the presence/absence of a defect of a micropattern image formed on a workpiece being tested such as reticle used in, for example, manufacturing of an LSI. [0004] 2. Description of the Related Art [0005] In general, since a lot of cost is required to manufacture an LSI, an increase in yield is inevitable. As one factor which decreases a yield, a pattern defect of a reticle used when a micropatterning image is exposed and transferred on a semiconductor wafer by a lithography technique is known. In recent years, with a miniaturization of LSI pattern size, the minimum size of a defect to be detected is also miniaturized. For this reason, a higher precision of a pattern inspection apparatus for inspecting a defect of a reticle is required. [0006] Methods of inspecting the presence/absence of a pattern defect are roughly classified into a method of comparing a die with a die (Die-to-Die comparison) and a method of comparing a die with a database (Die-to-Database comparison). The Die-to-Die comparison (DD comparison) is a method of comparing two dies on a reticle to detect a defect. The Die-to-Database comparison (DB comparison) is a method of comparing a die and a database generated from CAD data for LSI design to detect a defect. [0007] With micropatterning on a reticle, defects such as a pixel positioning error between images to be compared with each other, expansion and contraction and distortion of an image, defects which are small enough to be buried in sensing noise, must be detected. Even in the DD comparison or the DB comparison, alignment and image correction in a sub-pixel unit is very important in a pre-stage in which comparison and inspection of an inspection reference pattern image and a pattern image under test. [0008] Therefore, in the conventional pre-stage in which two images, i.e., an inspection reference pattern image and a pattern image under test are inspected by comparison, after alignment in units of sub-pixels based on bicubic interpolation is performed, a correction of expansion and contraction of an image (see, for example, Japanese Patent Application Laid-Open No. 2000-241136), a distortion correction of an image, a resizing correction, a noise averaging process, and the like are sequentially performed. However, a repetition of these corrections generates an accumulative error and serves as a main factor of deteriorating an image. Furthermore, setting of appropriate values a large number of parameters require for the respective corrections and setting of an appropriate order of the respective corrections are disadvantageously difficult. BRIEF SUMMARY OF THE INVENTION [0009] There is an image correcting method achieved by integrating alignment and image correction, having less image deterioration and a small number of setting parameters, and based on input/output model identification as effective image correction. For example, an inspection reference pattern image and a pattern image under test are used as input data and output data, respectively, to identify an input/output linear prediction model, and alignment in unit of a sub-pixel and image correction are simultaneously realized. In this case, a relational expression of matrixes is formed from the image data, and simultaneous equations are solved to identify a model parameter. At this time, in DB comparison, equal grayscale values continue in the inspection reference pattern image data (free from minute image sensor noise unlike in DD comparison), and a rank of a coefficient matrix of the simultaneous equations lacks, and it may be impossible to identify the model parameter. [0010] The present invention has been made in consideration of the above circumstances, and has as its object to provide an image correcting method which is effective when a rank of a matrix lacks by continuous equal grayscale values when an image is handled as a matrix in image correction in a pattern inspection apparatus such as a reticle inspecting apparatus. [0011] According to an embodiment of the present invention, there is provided an image correcting method for generating a correction image from pattern images of two types, including: the random noise pattern image generating step of generating a random noise pattern image at least in regions having almost equal grayscale values in the pattern image; and the random noise superposed image generating step of superposing the random noise pattern image at least on the regions having the almost equal gray scale values, and wherein the random noise pattern image has grayscale values which are finer than grayscale values of the pattern image. [0012] According to the embodiment of the present invention, there is provided an image correcting method for generating a correction image from an inspection reference pattern image and a pattern image under test, including: the random noise pattern image generating step of generating a random noise pattern image having grayscale values which are finer than the grayscale values of the inspection reference pattern image; and the random noise superposed image generating step of superposing the random noise pattern image on the inspection reference pattern image. [0013] According to the embodiment of the present invention, there is provided an image correcting method for generating a correction image from an inspection reference pattern image and a pattern image under test, including: the uninspected region setting step of setting uninspected regions in the two pattern images; the minimum grayscale value setting step of setting the grayscale values of the uninspected regions in the two pattern images as minimum calibration values; the random noise pattern image generating step of generating two random noise pattern images having grayscale values which are finer than the grayscale values of the two pattern images; and the random noise superposed image generating step of superposing the two random noise pattern images on the minimum calibration grayscale values in the two pattern images and the set uninspected regions, respectively. [0014] According to the embodiment of the present invention, there is provided an image correcting method for generating a correction image from an inspection reference pattern image and a pattern image under test, including: a random noise pattern image generating step of generating a random noise pattern image in at least a region having almost equal grayscale values in the inspection reference pattern image; a random noise superposed image generating step of superposing the random noise pattern image on at least the region having the almost equal grayscale values, the random noise pattern image having grayscale values which are finer than the grayscale values of the pattern images; a simultaneous equation generating step of generating simultaneous equations which describe an input-output relationship using, as an output, each pixel of the pattern image under test and using, as an input, a linear coupling of a pixel group around each corresponding pixel of the inspection reference pattern image on which the random noise is superposed; the simultaneous equation solving step of solving the simultaneous equations to estimate parameters of the prediction model; and the correction image generating step of generating a correction image by using the estimated parameters. BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING [0015] FIGS. 1A and 1B are schematic views of a two-dimensional linear prediction model used in a pattern image inspection method; [0016] FIG. 2 is a diagram showing the configuration of a concrete example of a pattern inspection apparatus; [0017] FIG. 3 is a diagram for explaining image acquisition by reticle scanning of a line sensor; [0018] FIGS. 4A and 4B are diagrams showing superposition of a random noise image having fine grayscale values; [0019] FIG. 5 is a diagram showing steps of an image correcting method; [0020] FIGS. 6A, 6B, and 6C are diagrams showing setting of an uninspected region and filling of random noise pattern image data having a fine grayscale; Continue reading about Image correcting method... Full patent description for Image correcting method Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Image correcting method patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Image correcting method or other areas of interest. ### Previous Patent Application: Visual inspection apparatus and method of inspecting display panel using the visual inspection apparatus Next Patent Application: Image correction method Industry Class: Image analysis ### FreshPatents.com Support Thank you for viewing the Image correcting method patent info. IP-related news and info Results in 0.84136 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m |
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